Polymer-Doped Ink System for Threshold Voltage Modulation in Printed Metal Oxide Thin Film Transistors.

A polymer-doped ink system was applied to a printed InO x thin film transistor (TFT), and enhancement mode devices were obtained with an appropriate polymer doping amount. As the polymer doping concentration (PDC) increases, the threshold voltage of thin film transistor shifts positively, while the mobility and subthreshold slope show only an insignificant degradation. The microanalysis shows that the polymer doping can generate traps and defects in the oxide lattice, thus shifting the threshold voltage positively and degrading the mobility and subthreshold slope. Meanwhile, the doping can also facilitate the formation of an oxide lattice in the local region, which counterbalances the effect of doping on the mobility and subthreshold slope. The InO x, the TFT shows good electrical performance at an optimal PDC of 0.3 wt %, with a mobility of 4.2 cm2 V-1 s-1, a threshold voltage of 0.7 V, an on/off ratio of 106, and a subthreshold slope of 0.30 V/dec.